Changes

If a road has a higher or lower type than what's specified in these rules, there may be a reason for it. Special rules are used to determine the road types of [[Creating and Editing a roundabout#Road type|roundabouts]] and [[At-grade connectors#How to label the connector type|at-grade connectors]].

==== Routing road type ====Apart from changing the nominal road type, level {{rank|routing}} editors can also change the [[Creating and editing road segments#Special properties|routing road type]] (also known as routing preference) to one type higher or lower, which only affects [[Routing server#Changes in routes due to different route lengths|long-distance aspects]] of road type behavior while maintaining the same appearance, [[How Waze determines turn / keep / exit maneuvers#Best Continuation|best continuation]] and [[Detour Prevention Mechanisms|detour prevention behavior]] of the nominal road type. These exceptions to the rules should be reviewed with local leadership before implementation.Special rules are used to determine the road types of [[Creating and Editing a roundabout#Road type|roundabouts]] and [[At-grade connectors#How to label the connector type|at-grade connectors]].

====Continuity====

[[File:35-71.png|thumb|300x300px|SR-435 has the Minor Arterial functional class , so it would normally have the Minor Highway road type in Waze. Since it is signed as the way from one Freeway (US-35) to another (I-71), it has the its routing road type Freewayhas been promoted to Major Highway, enabling the routing server to use it on routes from WV to IL. It's nominal road type remains Minor Highway to preserve appearance and detour prevention.]]

[[File:M55-66.png|thumb|300x300px|These Michigan State Trunkline Highways have the Minor Arterial functional class, so they would normally have the Minor Highway road type. However, even without signage indicating their longer-distance use, they have been upgraded to Major Highway in order to be used in routes between southwestern Michigan and the Upper Peninsula.]]

One common reason for a road to be set to a higher type is for the purpose of maintaining '''continuity''' between two roads with higher types. Promotion for continuity is usually indicated by signage: A certain less important road is signed as the way to get between two different more important roads.

For example, a freeway exit from I-70 is signed as "Exit 142: US-40 / Gratiot", indicating that this is the intended way to get to US-40, with Principal Arterial functional class. Between the ramps and US-40 is CR-30 with Local functional class. The rules on this page would normally dictate that this road be set to Primary Street, but in long-distance routing it may be removed from consideration, or '''[[Routing server#Pruning|pruned]]'''. This can be prevented either by assigning the Major Highway type outright or by assigning the Minor Highway type with a +1 routing road type, which would cause it to be treated like a Major Highway for long-distance routing. Use of routing road type is preferable to avoid unintended side effects on the behavior and display of the road.

Certain situations may require continuity upgrades even without signage to support them. Examples include but are not limited to:

* Connecting roads that may be too short to be noticed during state functional class assignment

When promoting for continuity, the effective road type of the connecting road should match the ''lower '' of the two roads that it connects, similar to type selection for at-grade connectors, up to Major Highway. This practice prevents Waze from pruning out valid routesSince Major Highway is never pruned, there is no need to promote something to Freeway with routing road type for continuity reasons alone, and in extreme cases can mean the difference between getting a good route and getting no route at allnominal Freeway road type should only be used for controlled-access highways that meet the criteria [[#Freeway|above]].

Continuity upgrades prevent Waze from pruning out valid routes, and in extreme cases they can mean the difference between getting a good route and getting no route at all.